VSIX install failed - visual-studio

Question

I downloaded extension in visual studio 2019 but while installing error occurred.
install log is this:
4/25/2021 8:41:33 PM - Microsoft VSIX Installer
4/25/2021 8:41:33 PM - -------------------------------------------
4/25/2021 8:41:33 PM - vsixinstaller.exe version:
4/25/2021 8:41:33 PM - 16.9.2017
4/25/2021 8:41:33 PM - -------------------------------------------
4/25/2021 8:41:33 PM - Command line parameters:
4/25/2021 8:41:33 PM - C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\Common7\IDE\VSIXInstaller.exe,C:\Users\Usman\Downloads\ProductivityPowerPack2017.vsix
4/25/2021 8:41:33 PM - -------------------------------------------
4/25/2021 8:41:33 PM - Microsoft VSIX Installer
4/25/2021 8:41:33 PM - -------------------------------------------
4/25/2021 8:41:34 PM - System.IO.FileLoadException: Could not load file or assembly 'Microsoft.VisualStudio.Validation, Version=15.3.0.0,
Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its
dependencies. The located assembly's manifest definition does not
match the assembly reference. (Exception from HRESULT: 0x80131040)
File name: 'Microsoft.VisualStudio.Validation, Version=15.3.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'
at VSIXInstaller.SupportedSKUs.AddInstalledIsolatedShells(Version
vsVersion, IntPtr userToken)
at VSIXInstaller.SupportedSKUs.InitializeSupportedSKUs(IntPtr userToken)
at VSIXInstaller.ExtensionService.InitializeSupportedSKUs(ICommandLineData
cmdLineData, IntPtr duplicatedUserToken)
at VSIXInstaller.App.Initialize(Boolean isRepairSupported)
at VSIXInstaller.App.Initialize()
at System.Threading.Tasks.Task`1.InnerInvoke()
at System.Threading.Tasks.Task.Execute()
--- End of stack trace from previous location where exception was thrown ---
at Microsoft.VisualStudio.Telemetry.WindowsErrorReporting.WatsonReport.GetClrWatsonExceptionInfo(Exception
exceptionObject)
WRN: Assembly binding logging is turned OFF.
To enable assembly bind failure logging, set the registry value [HKLM\Software\Microsoft\Fusion!EnableLog] (DWORD) to 1.
Note: There is some performance penalty associated with assembly bind failure logging.
To turn this feature off, remove the registry value [HKLM\Software\Microsoft\Fusion!EnableLog].

Answer 1

Run a repair of your Visual Studio installation.

Answer 2

If repair doesn't work, you might've moved your VS install and now it won't install anything.
This is because it "might" be finding the VS Installer in a directory OTHER than the standard one. Reinstall the installer itself, then try to install the extension or whatevs

Answer 3

Check if this path exists on your C drive. The "Packages" folder is used to save VS extensions which VS needs. I'd moved mine to F drive to save space. The error message didn't help me much.
C:\ProgramData\Microsoft\VisualStudio\Packages